Lipase-mediated transformation of D-xylose and D-galactose into less common L-aldoses

Gamalevich, G. D.; Morozov, B. N.; Vlasyuk, A. L.; Serebryakov, É. P.

doi:10.1070/mc1998v008n03abeh000965

Cited by 4 publications

(5 citation statements)

References 18 publications

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Section: Resultscontrasting

confidence: 65%

“…The optical rotations obtained by us for the alcohols SR ‐8 ([α] D 25 = −21.4) and RS ‐8 ([α] D 25 = +18.3) were much larger than those previously published 17−20. Furthermore, the optical rotations for the alcohols SS ‐8 ([α] D 25 = −2.41) and RR ‐8 ([α] D 25 = +2.58) prepared by us were significantly smaller than those previously reported 17−21. Most of the previously published syntheses17−20 involved catalytic hydrogenation of an enantiomerically enriched unsaturated alcohol with the stereogenic centre located between the alcohol and the double bond.…”

Section: Resultscontrasting

confidence: 65%

“…Furthermore, the optical rotations for the alcohols SS ‐8 ([α] D 25 = −2.41) and RR ‐8 ([α] D 25 = +2.58) prepared by us were significantly smaller than those previously reported 17−21. Most of the previously published syntheses17−20 involved catalytic hydrogenation of an enantiomerically enriched unsaturated alcohol with the stereogenic centre located between the alcohol and the double bond. In many cases, reductions are known to give a certain degree of epimerisation,13,22−26 leading to lower than expected stereoisomeric purity at C‐6 in the final products.…”

Section: Resultsmentioning

confidence: 62%

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Syntheses of the Sixteen Stereoisomers of 3,7,11-Trimethyl-2-tridecanol, Including the (2S,3S,7S,11R) and (2S,3S,7S,11S) Stereoisomers Identified as Pheromone Precursors in Females of the Pine SawflyMicrodiprion pallipes(Hymenoptera: Diprionidae)

et al. 2001

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All sixteen stereoisomers of 3,7,11‐trimethyl‐2‐tridecanol were synthesised in high stereoisomerical purities (> 95%), for use in the identification of the stereoisomers present in females of the pine sawfly Microdiprion pallipes (Fallén) (Hymenoptera: Diprionidae) as the precursor of the actual sex pheromone (which is the propionate), and also for investigation of the biological activities of the esters. The key step in the syntheses was the coupling of each of the enantiomers of cis‐3,4‐dimethyl‐γ‐butyrolactone with each of the four pure stereoisomers of 1‐lithio‐2,6‐dimethyloctanes. The four corresponding alcohols were obtained by lipase‐catalysed (Amano PS) kinetic separation, based on selective acylation of either (2R/S,6S)‐ or (2R/S,6R)‐2,6‐dimethyl‐1‐octanol (obtained from the optically pure enantiomers of citronellal). Additionally, a mixture of the 16 possible stereoisomers of 3,7,11‐trimethyl‐2‐tridecanol was also prepared.

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Section: Resultscontrasting

confidence: 65%

Section: Resultscontrasting

confidence: 65%

Section: Resultsmentioning

confidence: 62%

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Syntheses of the Sixteen Stereoisomers of 3,7,11-Trimethyl-2-tridecanol, Including the (2S,3S,7S,11R) and (2S,3S,7S,11S) Stereoisomers Identified as Pheromone Precursors in Females of the Pine SawflyMicrodiprion pallipes(Hymenoptera: Diprionidae)

et al. 2001

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“…Acetate (S)-IVa and alcohol (R)-IV were obtained in 100% and 70% yields, respectively, via partial acylation of the metal complex (RS)-IV using vinylacetate, PPL, and Et 2 O [9] (with 47 -51% conversion at 20°C) followed by chromatography of the products over a column of SiO 2 using a hexane: Et 2 O gradient ( Target acids (R)-and (S)-I were synthesized by the same scheme. The Wittig reaction was carried out using a very slight excess of PTPC (~1.2 eq.)…”

Section: Increase Of Enzymatic Enantioselective Separation Of (Rs)-iimentioning

confidence: 99%

Synthesis of the Racemate and Both Enantiomers of Biologically Active 4-(2,6-Dimethylheptyl)Benzoic Acid and Their Effect on Cholesterol Accumulation in Aorta Cells

2015

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A chemical and enzymatic approach to the synthesis of (S)-and (R)-3-(4-methoxycarbonyl)phenyl-2-methyl-1-propanols, convenient intermediates for the synthesis of both enantiomers of 4-(2,6-dimethylheptyl)benzoic acid, was described. The biological activity of (R)-and (S)-isomers of the racemic acid was studied. It was established that the (S)-configuration of its antipode in the racemate decreased the cholesterol level in aorta cells.Keywords: (R)-and (S)-4-(2,6-dimethylheptyl)benzoic acids, (S)-and (R)-3-(4-methoxycarbonyl)phenyl-2-methyl-1-propanols and their h 6 -chromiumtricarbonyl complexes, porcine pancreatic lipase (PPL), aorta cholesterol level.Racemic 4-(2,6-dimethylheptyl)benzoic acid [(RS)-I] reduces effectively the in vivo blood level of excessive cholesterol [1] and also suppresses cholesterol accumulation in human atherosclerotic aorta cells in culture [2] more strongly that standard Clofibrate ® . This makes it promising in the battle with atherosclerosis. However, the pharmacological properties of the pure enantiomers (R)-I and (S)-I have not been previously studied because the acids themselves were unknown.We developed previously [3] a stereo-divergent synthetic scheme in order to synthesize the undescribed acids (R)-I and (S)-I from the common precursor enal II [4] through racemic alcohol (RS)-III. The scheme included enzymatic kinetic separation of (RS)-III using porcine pancreatic lipase (PPL).The PPL-catalyzed kinetic separation of the (RS)-acetate of 3-(4-methoxycarbonyl)phenyl-2-methyl-1-propanol produced the (R)-III and (S)-III enantiomers of the corresponding alcohol with 22 -27% optical purity. The enantiomeric excess (ee) could not be increased above 33% with repeated enzymatic hydrolysis of the "residual" acetate under the same conditions. Partial acylation [5] of (RS)-III alcohol using vinylacetate-Candida cylindracea (CCL) also did not give products with the required high enantiomeric purity.The limited choice of lipases with high enantiomeric selectivity for racemic substrate (RS)-III and the desire to synthesize pure enantiomers of (R)-III and (S)-III with an acceptable ee for synthesizing target acids (R)-I and (S)-I prompted us to seek new approaches for solving this problem.Examples where the selectivity of lipases was increased by adding chemical additives to the reaction mixture were reported. The addition of them could have a favorable effect on the enzyme microenvironment [6,7]. Amines, crown ethers, moistened sodium or lithium salts, and various combinations of enzymes with added Group IV -VII elements (Si, Cr, Ru) were used as such additives.We settled on a previously unused approach, i.e., a drastic change of the electronic and steric properties of the substrate by converting it into the corresponding racemic arene(tricarbonyl)chromium complex of alcohol (RS)-IV [5] and/or its acetate (RS)-IVa [8].

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“…Acid I (m.p., 73 -74; recrystallized from MeOH-H 2 O) was obtained in the form of whiskers using a method described in [15]. The synthesis of acid II and amide VII was described elsewhere [3].…”

Section: Experimental Chemical Partmentioning

confidence: 99%

Antiatherosclerotic properties of 4-(2,6-dimethylheptyl)-and 4-(2,6,10-trimethylundecyl)benzoic acids and their amides

et al. 2006

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Two amides with polyol-rich moieties and two other analogs with N-(b-aminoethyl)amide groups, all derived from 4-(2,6-dimethylheptyl)benzoic acid (I), and two polyol amides derived from 4-(2,6,10)-trimetylundecyl)benzoic acid (II) were synthesized and tested for antiatherosclerotic activity in vitro. None of the amides prevented excessive accumulation of cholesterol in the culture of smooth muscle cells (SMCs) raised from human aorta sclerotic plaque, although polyol amides from acid I inhibited protein synthesis in this cell culture. In human liver homogenates (HLHs) all amides derived from acid I accelerated the human cholesterol esterase-catalyzed hydrolysis of cholesteryl palmitate. Acid I displayed antiatherosclerotic effects in both SMC and HLH assays, while acid II and its amides were ineffective in either of these test systems.

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Lipase-mediated transformation of D-xylose and D-galactose into less common L-aldoses

Cited by 4 publications

References 18 publications

Syntheses of the Sixteen Stereoisomers of 3,7,11-Trimethyl-2-tridecanol, Including the (2S,3S,7S,11R) and (2S,3S,7S,11S) Stereoisomers Identified as Pheromone Precursors in Females of the Pine SawflyMicrodiprion pallipes(Hymenoptera: Diprionidae)

Syntheses of the Sixteen Stereoisomers of 3,7,11-Trimethyl-2-tridecanol, Including the (2S,3S,7S,11R) and (2S,3S,7S,11S) Stereoisomers Identified as Pheromone Precursors in Females of the Pine SawflyMicrodiprion pallipes(Hymenoptera: Diprionidae)

Synthesis of the Racemate and Both Enantiomers of Biologically Active 4-(2,6-Dimethylheptyl)Benzoic Acid and Their Effect on Cholesterol Accumulation in Aorta Cells

Antiatherosclerotic properties of 4-(2,6-dimethylheptyl)-and 4-(2,6,10-trimethylundecyl)benzoic acids and their amides

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